Kikusui TOS9213S Operation Manual page 48

[28] Protective conductor terminal
[29] Cord holder
CAUTION
4-8
This is a terminal for grounding the tester when you connect it to an ungrounded
outlet. For details, see "2.5 Connecting the AC Power Cord".
Holder for the power cord.
• Do not place the tester on sides other than the bottom surface. Leaving the
cord holder beneath the tester makes it extremely unstable, and is
extremely dangerous.
TOS9213S/ TOS9213AS